"Well, the first thing to say is that we've worked hard to maintain compatibility, so that any program written with an earlier version of Mathematica can run without change in 3.0, and any notebook can be converted."

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People don't scream or swear or pout or sulk when there's compatibility. But most growth occurs when there's incompatibility. When it comes to resilience, when it comes to pulling yourself up when you've fallen down, you don't learn those things when things are going well. You learn those things when you're struggling.

— Ross W. Greene